<template>
  <div>
    <span>全选:</span>
    <input type="checkbox" v-model="isAll"/>
    <button @click="toggle">反选</button>
    <ul>
      <li v-for="item in arr" :key="item.name">
        <input type="checkbox" v-model='item.c' />
        <span>{{item.name}}</span>
      </li>
    </ul>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [
        {
          name: "猪八戒",
          c: false,
        },
        {
          name: "孙悟空",
          c: false,
        },
        {
          name: "唐僧",
          c: false,
        },
        {
          name: "白龙马",
          c: false,
        },
      ],
    };
  },

  methods:{
    toggle() {
      this.arr.forEach(item => item.c = !item.c)
    }
  },

  computed: {
   isAll:{
    get() {
      return this.arr.every(item => item.c)
    },

    //在这个计算属性被改变的时候会调用set方法
    //value就是计算属性即将被改变的值
    set(value) {
      this.arr.forEach(item => item.c = value)
    }
   }

  }
};
</script>

<style>
</style>